DAS uncovered: Exploring the genius behind Mercedes’ banned innovation

Uros Radovanovic
Lewis Hamilton in the Mercedes W11.

The all-conquering Mercedes W11 featured the DAS system in 2020, which was quickly outlawed for 2021.

With the F1 2023 season done and dusted, let’s go down memory lane and take a look at some of the best technical innovations ever seen in F1. First up: DAS.

DAS, or Dual-Axis Steering, is one of those technical breakthroughs in Formula 1 that, due to its sheer brilliance, had a short lifespan because the FIA had to change its rules just because of it.

Let’s uncover what exactly hid behind this system, how it functioned, and the advantages and disadvantages it brought to Mercedes in 2020.

F1 steering system basics

To understand this concept properly, we must start from the beginning and grasp some basic principles of the steering system. Formula 1 cars are so complex and operate at such a high technical level that even the smallest details can make significant differences on the track.

Engineers have the freedom to play around with various steering system parameters, including toe. Toe represents the angle of the wheels concerning the car’s imaginary perfect straightforward direction. This angle can be adjusted from race to race, adapting to different track types.

Perfectly aligned wheels represent zero toe. Wheels with positive toe will point inwards, towards the car’s centerline, while negative toe will make them splay outwards—simpler and more commonly used terms are “toe in” and “toe out.”

Additionally, you might come across the term “toe distance” as some measure this angle with distance. But what benefits do teams gain from changing the wheel angle?

How does it make a difference on the track?

Toe has an impact on several segments, primarily on tyre temperature, car stability and handling in corners.

If we imagine a car on a straight track with zero toe, the wheels are positioned perfectly straight and freely rotate around their axes. However, applying a toe will cause certain parts of the tyre to “drag” along the track, creating additional friction. More friction means increased temperature, faster tyre wear, but also lower maximum speeds on straights.

Toe in increases the temperature on the outer part of the tyre, while toe out affects the inner part, referring to a surface approximately 5 centimetres wide.

Moreover, the toe significantly influences the car’s stability in turns. If you envision a car turning through a corner, you can see that the outer tyre on the upper and lower axes covers a greater distance compared to the inner tyre.

However, when you have a toe out on the front axle, the wheels enter the turn at a completely different angle. In this case, the inner tyre “steers more” due to a greater angle concerning the car’s centerline.

As a result, the car has much more stability and rotates more easily in corners compared to zero toe—why toe out is commonly applied to the front axle of a car. On the other hand, toe in reduces the car’s ability to turn, which is not ideal for turns but brings stability on straights.

In essence, toe is a trade-off that brings both good and bad on the track. Engineers have the task of adjusting this angle to bring positive changes in performance.

Although it may not bring drastic changes, we must consider that a Formula 1 race is a marathon where details can easily accumulate and ultimately make a big difference.

Additionally, it’s crucial that this parameter fits well with others, such as front stiffness, front camber, front anti-roll, and many more.

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How did Mercedes utilise toe adjustment?

During the first day of testing in Barcelona before the 2020 season, all teams noticed something unusual with the steering wheel on Mercedes’ cars.

Rules state that the position of the steering wheel can affect the position of the front tyres, but nobody had thought of ideas like this before. This is a perfect example of where the engineers’ genius and creativity come to the forefront, making a direct difference on the track.

Mercedes did not break any rules but simply found a loophole in the regulations that allowed them to implement the DAS system.

The DAS system worked by allowing the driver, in addition to the rotational movement of the steering wheel, to move the steering wheel closer to or farther from themselves. In this way, they could adjust the toe angle whenever they wanted—opening up a whole new dimension.

Specifically, Mercedes’ drivers would pull the steering wheel towards themselves on straights, putting the wheels in a zero toe or very small toe in position.

When they approached a straight and started preparing for braking, they would simply push the steering wheel slightly away from themselves, creating a toe out, which is highly desirable in turns.

However, what truly made a difference was the ability to make fine adjustments that would prepare the front wheels exactly as needed for a specific turn. It’s worth noting that we’re talking about very small angles, around two degrees, making it challenging to notice these changes.

Moreover, as mentioned earlier, the DAS system also influenced tyre temperature. The ability for the driver to independently adjust the temperature and decide which part of the tyre they wanted to heat up better is incredible.

This certainly helped Mercedes in some unforeseen situations, such as when the Safety Car is out, and you want to maintain tyre temperature as best as possible. This can be significant even in the preparatory lap of qualifying, where these tiny details have an even greater impact on the final time.

What were the results of the DAS system?

As we know, Mercedes simply dominated throughout the 2020 season. They won 13 out of the total 17 races that year, which is an outstanding result. Many consider the Mercedes car from that year to be one of the fastest in the history of Formula 1, breaking multiple lap records on its way to Drivers’ and Constructors’ glory.

Although many teams filed complaints about the DAS system, all were rejected, and the system was declared entirely legal. However, to prevent other teams from developing it, the FIA decided to change the rules, meaning that DAS could only be used in the 2020 season.

DAS was not the main reason behind the success of the 2020 season, and without it, the dominance from Mercedes would still be present – but do not let that detract away from an absolutely incredible innovation.

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